A synthetic antiferromagnetic structure for a spintronic device is disclosed and has an FL2/Co or Co alloy/antiferromagnetic coupling/Co or Co alloy/CoFeB configuration where FL2 is a ferromagnetic free layer with intrinsic PMA. Antiferromagnetic coupling is improved by inserting a Co or Co alloy dusting layer on top and bottom surfaces of the antiferromagnetic coupling layer. The FL2 layer may be a L10 ordered alloy, a rare earth-transition metal alloy, or an (A1/A2)n laminate where A1 is one of Co, CoFe, or an alloy thereof, and A2 is one of Pt, Pd, Rh, Ru, Ir, Mg, Mo, Os, Si, V, Ni, NiCo, and NiFe, or A1 is Fe and A2 is V. A method is also provided for forming the synthetic antiferromagnetic structure.
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2. The method of claim 1, wherein the seed layer is TaN/Mg/X, Ta/X, or Ta/Mg/X where X is NiCr or NiFeCr, or the seed layer has a Ta/M1/M2 composition where M1 is Ru, and M2 is one of Cu, Ti, Pd, Pt, W, Rh, Au, or Ag.
3. The method of claim 1, wherein the ferromagnetic layer is an AP2 reference layer comprised of an (A1/A2)n laminate where the lamination number “n” is less than 6, A1 is one of Co, CoFe, or an alloy thereof, and A2 is one of Pt, Pd, Rh, Ru, Ir, Mg, Mo, Os, Si, V, Ni, NiCo, and NiFe, or A1 is Fe and A2 is V, or the AP2 reference layer is made of a L10 ordered alloy of the form MT wherein M is Rh, Pd, Pt, Ir, or an alloy thereof, and T is Fe, Co, Ni or alloy thereof, or the AP2 reference layer is made of a rare earth-transition metal alloy that is TbCo, TbFeCo, or GdFeCo.
4. The method of claim 1, wherein the ferromagnetic layer is a FL2 free layer comprised of an (A1/A2)n laminate where the lamination number “n” is less than 6, A1 is one of Co, CoFe, or an alloy thereof, and A2 is one of Pt, Pd, Rh, Ru, Ir, Mg, Mo, Os, Si, V, Ni, NiCo, and NiFe, or A1 is Fe and A2 is V, or the AP2 reference layer is made of a L10 ordered alloy of the form MT wherein M is Rh, Pd, Pt, Ir, or an alloy thereof, and T is Fe, Co, Ni or alloy thereof, or the AP2 reference layer is made of a rare earth-transition metal alloy that is TbCo, TbFeCo, or GdFeCo.
5. The method of claim 1, wherein the CoFeB layer has a thickness from about 6 to 12 Angstroms.
7. The method of claim 1, further comprising sequentially forming a tunnel barrier layer made of a metal oxide, a free layer with PMA, and a cap layer on a top surface of the CoFeB layer to form a MTJ stack of layers, the tunnel barrier induces additional PMA in the CoFeB layer.
8. The method of claim 7, further comprising annealing the MTJ stack with a temperature between about 200° C. and 500° C. for a period of about 5 minutes to 10 hours.
10. The method of claim 9, wherein the ferromagnetic layer is an (A1/A2)n laminate where n is an integer less than 6, A1 is one of Co, CoFe, or an alloy thereof, and A2 is one of Pt, Pd, Rh, Ru, Jr, Mg, Mo, Os, Si, V, Ni, NiCo, and NiFe, or A1 is Fe and A2 is V.
11. The method of claim 9, wherein the ferromagnetic layer is a L10 ordered alloy of the form MT wherein M is Rh, Pd, Pt, Jr, or an alloy thereof, and T is Fe, Co, Ni or alloy thereof, or the FL2 layer is made of a rare earth-transition metal alloy that is TbCo, TbFeCo, or GdFeCo.
12. The method of claim 9, wherein the ferromagnetic layer is a (A1/A2)n laminate where n is a lamination number, A1 is one of Co, CoFe, or an alloy thereof, A2 is one of Rh, Ir, Ru, Os, Mo, or an alloy thereof and A2 provides ferromagnetic or antiferromagnetic coupling between neighboring A1 layers when n is between 2 and 10.
13. The method of claim 9, wherein the ferromagnetic layer is a reference layer.
14. The method of claim 9, wherein the ferromagnetic layer is a free layer.
17. The method of claim 16, wherein the seed layer includes Ta, Mg, Ni and Cr.
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December 14, 2020
March 12, 2024
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